Method of forming reinforced-concrete posts or the like.



v H. A. LANDWEHR.

METHOD OF FORMING REINFORCED CONCRETE POSTS OR THE LIKE.

APPLICATION FILED SEPT-3,19I8.

Patented Apr. 8, 1919.

2 SHEETS-SHEET I.

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HENRY a. LANDWEHR, or LOS ANGELES, CALIFORNIA, ASSIGNOR T0 AMERICAN CEMENT rnonuo'rs cor/man or LOS ANGELES, CALIFORNIA, a conroaafrom or CALIFORNIA.

METHOD OF FORMING REINFORCED-CONCRETE POSTS OR THE LIKE.

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Specification of Letters Patent.

Application filed September 3, 1918. Serial No. 252,343.

To. all whom it may concern:

Be it known that I, HENRY A. LANDWEHR, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles, State of California, have invented new and useful Improvements in Methods of- Formparticularly to an improved method of plac-: ing and sustaining longitudinally extendingreinforcements and the method of holding such reinforcements in place during the formation of the concrete by molding andby-t centrifugal action.

So far as I am ware such reinforced posts" as I herein explain, which have been foii'ned by the centrifugal method, have been heretofore provided with internal metallic reinforcements, consisting usually of longitudinally extending reinforcing rods joined together transversely by connecting rods .or

1 wires, sometimes wound helically about and attached to the longitudinal rods, Such reinforcements have heretofore been usually held in place during the formation of the concrete by some interior support or by an exterior supporting means, or by transversely projecting portions of the reinforcing elements which extend to contact with theinterior surfaces of the mold. All of these methods have their objectionable features in that some special supporting means must be used or in that the projecting supporting parts of the reinforcements extend to the exterior of the finished post or other article.

It is a particular object of this invention to provide a simple and eflective method of procedure whereby the reinforcements are longitudinally strained into position and whereby the reinforcements are effectually held in accurate central and concentric relation to the mold during the rotation of the mold for the centrifugal formation of the concrete.

This application is in the nature of 9, con-. tinuation in part of my application on reinforced concrete posts and method of making same, filed Nov, 17, 1916, Serial No. 131,821.

My method will be best understood from the following detailed description of the finished product and of a preferred form of apparatus by which the method may be carried out, For the purpose of this description ,1". refer to the accompanying drawings in Which Figure 1 is an elevation of a finished post parts being shown in section; Fig. 2 is a central vertical secti n of the upper part of the finished post; Fi 3 is a horizontal section taken as indicated by line 3+8 on Fig. 1; Fig. 1 is a central vertical section of the lower part of a finished post; Fig. 5 is an enlarged longitudinal section showing the mold and a post in process of formation;

Fig. 6 is an .end view of the apparatus shown in Fig. 5 Fig. 7 is an enlarged detail section taken as indicated by line 77 on Fig. 6' Fig. 8 is a transverse section on line 88 of Fig. 5'; Fig. 9 is a detail View taken as indicated by line 9-9 on Fig. 8; Fig. 10 is an end viewof a modified form; and Fig. 11 is a longitudinal section of the end of the form. shown in Fig. 10.

I shall first explain the form of post shown in Figs. 1 to 4; then explain the method of formation and the apparatus used therefor; and then explain the modified forms of apparatus. The drawings show a post made up of a cementitious body 10 with suitable reinforcements. The cementitious body maybe made in any style or character desired, and is preferably, by the centrifugal process, made with. an interior longitudinal opening 11 extending from end to end of the post. The exterior; ornamentation of the post may teas desired; I illustrate a form of post which is being put into extensive use and is being manufactured by the centrifugal process, in the-manner I hereinafter explain. The post has a base 12, and in this base (in the preferred form shown in Figs.

Patented m. a, rare.

1 and 2, and shown in formation in Figs. 5,

6 and 7) 1 embed the foot brackets 13. These foot brackets 13 are arranged in the manner shown in Figs. 3 and a, with their horizontal parts extending out beyond the edges of the base to afford facility for connection with the foundation bolts 14 and with their preferably hooked into the foot brackets-13,

in the manner shown. These reinforcing rods 16 are preferably four in number, as are also the foot brackets, and converge first inwardly and upwardly toward each other and olts 18. In the finished post these bolts 18 project up through a cap plate 19; and nuts 20 hold the cap plate down and hold the reinforcing rods under their proper tension. Thecap plate 19 may be a part of fixture 19 which includes a lamp socket and a shade holder. The plate 19 bears down on the,

inner flange 19 of the shade holder as well as bearing down on the upper end of the post. The four reinforcin rods 16 are l-aterally connected by cross wires 22 which are also embedded in the concrete around the central opening 11. These wires '22 are twisted around each reinforcing rod 16 and are arranged diagonally transversely; so

that the whole reinforcing structure forms substantially a long square reinforcing skeleton with therods 16 at the four corners. The reinforcing rods and wires being embedded in the concrete, and the rods being connected and more or less stressed between the upper cap and the lower feet of the post, it Wlll be seen that the post is efficiently and strongly reinforced. And this 1s particularly true because of the fact that the concrete itself is veryclosely and densely formed around the reinforcements, due' to thepeculiar action of the centrifugal process which throws the concrete to the'outside and the water to the inside, making a voidless, non-porous concrete body.

Concrete posts, such as herein described are formed in such moldsas are illustrated in Figs. 5 and following. In Fig. 5 I show a typlcal mold having a central exterior metal shell 30 with mold lining 31 of suitable material, such as wood or metal,.and head and base shells 32 and 33 with wooden mold linings 34 and 35. These molds may be parted in any desired mannenas on the partlng lines shown at 35 in Figs. 6 and 8. These parting lines are preferably three in number as that system of parting allows the free withdrawal of the mold from the figured surface of the formed concrete and from the hexa onal base 12-. The parts of the mold bo y may be held together by means as shown at 60; embodying both lugs 61 at nuts 64 on the bolts, The bolts may be aeaeaa quickly released by removing the wedges and the nuts may be slightly loosened to plate 39 is likewise provided and similarly secured to the base shell 33 by means of wedges 40. suitably shaped core 41 for forming the hollow interior 42 of the base of the post. During formation foot brackets 13 are held in place by being placed against base plate 39 within metal boxes 43. Cap screws or other suitable fastening means 43 pass through apertures 44 in the base plate and through the apertures 45 in the foot brackets and then screw into the 'boxes 43 at 46; thus holding the foot brackets 13 rigidly to the base plate, and holding the boxes 43 in place. These boxes are open on their inner ends to receive the foot brackets, and are preferably open on their bottoms so that the foot brackets bear directly against the bottom plate 39, and are preferably closed at their outer ends. The boxes reach the outer surface of the mold and are removable out- This base plate 39 carries a wardly when the mold is to be taken off the formed'post and when the bolts 43 are removed. The removal of these boxes leaves a clear opening around the projecting parts of brackets 13 sufficient to allow the separation of the mold parts on the parting lines. The lower ends of the reinforcements having been secured to the foot brackets, the upper ends of the reinforcements are then secured by the bolts 18 being passed through the cap plate 37 ofthe mold and the nuts 20 being screwed down upon. the cap plate to draw the reinforcing rods 16 tightly into their proper positions, and to properly stretch the; reinforcing rods. The tendency of the reinforcing rods to straighten out and to move apart is resisted by the transverse tie wires 22. The reinforcements are held tightly stretched in a position centering about the longitudinal center of the mold;

so that, during the subsequent rotation, there I is no tendency of the reinforcements to be displaced from their proper position.

The mold having been assembled, and the reinforcements put .in place, as described, the concrete mixture is next placed in the mold. Thisconcrete mixture may have a superfluity ofwater; and the volume of the mixture and the proportion ofwater are ascertained by experience and gaged accordingly; so that, when the water is separated from the concrete by the centrifugal action, the resulting solidified body of. concrete will leave a central longitudinal opening. The

mold having been filled with the fluid concrete, the base is closed by its cap 50; the;- mold is placed in its horizontal position and v is placed in the revolving machine, where it is revolved about its central axis at a suitable speed for the required time period to cause the concrete to solidify in the form illustrated. After the concrete has set it may be removed from the mold and subjected to any treatment desired.

It will be seen that a feature of this arrangement lies in the fact that the reinforcements are, during formation, extended and bolts also extending through the base plate 39 of the mold. These base bars 13 are substantially equivalent to the foot brackets 13, except in the manner. of connection of the reinforcing rods 16 with them.

A distinctive feature of the method which I herein set forth is the longitudinal straining of the longitudinally extending reinforcements through the length of the mold, in concentric relation thereto; so that by this longitudinal straining the reinforcements are held in their proper central position durin the rotation of the mold and the rotation of the concrete charge therein. In this relation the transverse tying of the longitudinal rods plays an important part. By these ties the central parts of the longitudinal rods are drawn and held inwardly toward each other; so that each rod is bent inwardly in its central portions toward the central axis of rotation of the mold. The reinforcing structure thus formed, and longitudinally stressed between the ends of the mold, is not displaced from its proper central concentric position by centrifugal forces generated by rotation of the mold, or by outward pressure of the concrete being thrown to the outer parts of the mold. It will be seen that any tendency for the reinforcing system to move laterally out of its central position immediately causes a strain which tends to lengthen or stretch one or more of the longitudinal rods. In other words, the reinforcing system cannot move laterally in one direction without stretch ing one or more of the rods on the side opposite that toward which movement tends to take place. Consequently, with the rods stressed into position, and particularly with the rods stressed in their bent position as described, the whole reinforcing system is held rigidly in proper central alinement. Moreover, the centrifugal force, acting upon the tie wires 22, and the outward pressure of the concrete upon these tie wires, (which are initially stressed by the stressing of longitudinal rods 16) tends to draw the longitudinal rods somewhat inwardly toward' eachother and to further tighten those rods; and thus tends to make the whole system more rigidly and effectively resist any tendency to transverse displacement.

Further, the reinforces thus initially stressed are held in'that stressed condition by the formed and set concrete; so that the finished concrete post is effectively held together and reinforced.

Having described a preferred form of my invention, I claim:

1. The herein described method of forming reinforced concrete posts or the like by the centrifugal process, embodying the longitudinal tensioning of a reinforcing system in a mold. substantially concentric with the axis thereof, placing wet plastic concrete in the mold, and rotating the mold about its axis, as and for the purposes specified.

2. The herein described method of forming reinforced concrete posts or the like by the centrifugal process, embodying the longitudinal tensioning of a system of longitudinal reinforcing rods through a mold in substantially symmetrical arrangement about the axis of the mold, drawing and securing the rods transversely inwardly toward each other in their central portions, placing a suitable charge of plastic concrete in the mold, and rotating the mold about its axis, as and for the purpose specified.

In witness that I claim the foregoing I have hereunto subscribed my name this 6th day of July 1918.

HENRY A. LANDWEI-IR.

Witness VIRGINIA I. BERINGER. 

